Circuit breaker



Jan. 18, 1955 H. J. LINGAL 2,700,032

CIRCUIT BREAKER Filed Sept. 28, 1953 5 Sheets-Sheet l WITNESSES:INVENTOR Jan. 18, 1955 H. ,J. LINGAL 2,7 ,082

cmcum BREAKER Filed Sept. 28, 1953 5 Sheets-Sheet 2 WITNESSES:

INVENTOR glarry J.Lin gcll.

ATTORNE Jan. 18, 1955 H. J. LINGAL cmcurr BREAKER 5 Sheets-Sheet 4 FiledSept. 28, 1953 1 Fig.5.

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OVER-CURRENT TRIP RATING AMP5.S. PICKUP AMPERES INVENTOR Hurry J.Lina1lf;%/

WITNESSES: Z4? 77 gal.

ATTORNEY United States Patent 6 CIRCUIT BREAKER Harry J. Lingal,Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application September 28,1953, Serial No. 382,748

7 Claims. (Cl. '200-98) This invention relates to circuit breakers andmore particularly to circuit breakers of the type used for controllinglight to moderate power distribution circuits.

In certain circuit breaker applications, for instance, where a circuitbreaker is to be applied in a selective tripping system as a sourcebreaker or as a bus tie or group feeder breaker, the breaker is equippedwith an overcurrent trip device which trips the breaker with a timedelay on all values of overload currents up to the interrupting capacityof the breaker. With the breaker latched in the closed position, thebreaker will carry such excessive overload currents for some timewithout damage to the breaker and will then interrupt the circuit.

If an attempt is made to close the breaker against a fault current onthe line the breaker would likely be severely damaged. The reason forthis is that the large magnetic forces which tend to blow the contactsapart are greater than the force applied by the closing mechanism toclose the contacts. Merely providing greater closing force does notsolve the problem because the greater closing force would, when closingthe breaker with a normal current on the line, cause damage to thebreaker.

An object of the invention is to provide a circuit breaker having a tripdevice embodying time delay tripping means and means for tripping thebreaker instantaneously only when the breaker is closed with a fault onthe line.

Another object of the invention is to provide a circuit breakerembodying time delay and instantaneous tripping means 'with means forenergizing the instantaneous tripping means only during a closingoperation.

.Another object of the invention is to provide a circuit breaker havinga normally ineffective instantaneous trip means with means for renderingthe instantaneous trip means etfective only during a closing operationof the breaker.

The invention, both as to structure and operation, together withadditionalobjects and advantages thereof, will be best understood fromthe following detailed description thereof when read in conjunction withthe accompanying drawings.

In said drawings:

Figure 1 is an elevational view, partly in section, of a circuit breakerembodying the principles of the invention.

Fig. 2 is a vertical sectional view through the center pole of thebreaker.

Fig. 3 is a vertical sectional view through the trip device.

Fig. 4 is a sectional plan View of the time delay device takensubstantially along line IVIV of Fig. 3.

Fig. 5 is a fragmentary sectional view taken on line VV of Fig. 4showing the short-time delay valve device and the adjusting meanstherefor.

Fig. 6 is an elevational view of apart of the time delay device showingthe scale plate and the several adjusting knobs.

Fig. 7 is a schematic View of the circuit breaker including a diagram ofthe control circuit for energizing the instantaneous trip means.

Fig. 8 is a schematic view of the trip device illustrating the severaladjusting means for the time delay device.

The invention is illustrated as applied to a circuit breaker of the typefully disclosed in copending application Serial No. 141,136, filedJanuary 20, 1950, byJohn B. MacNeill, Fritz E. Florschutz, TureLindstrom-and spaced side members (only one being Bernard G. Tremblayand assigned to the assignee of this application.

Referring to Fig. 2 of the drawings, the circuit breaker includes aplurality of pole units each comprising a contact structure indicatedgenerally at 11, and an overcurrent trip device indicated generally at13. The contact structure and the trip device for each pole unit aremounted on a separate insulating base which is rigidly secured to ametal panel 17.

The insulating base 15 for the center pole unit (Fig. 2) is secured tothe panel 17 by means of screws 19 threadedly engaging metal inserts 21molded integral with the insulating base 15.

The contact structure 11 comprises a stationary main contact 23 and astationary arcing contact 25, both of which are secured on the inner endof a terminal condoctor 27 which extends through suitable openings inthe insulating base 15 and in the metal panel 17.

Cooperating with the stationary main and arcing contacts 23 and 25,respectively, is a movable main contact 33 and a movable arcing contact35. The movable main contact 33 is mounted on a pivoted contact carryingmember 3'7 and the movable arcing contact 35 is suitably mounted on thecontact carrying member 37.

The contact carrying member 37 is pivotally mounted by means of a pivotpin 41 on the upper or free end of a generally channel-shaped switch arm43 having its two sides pivoted by means of separate pivot pins 45 onspaced brackets 47 mounted on the base 15.

The contact carrying member 37 is electrically connected by means of aflexible conductor 51 to the energizing coil of the trip device 13 to belater described. A spring 57 compressed between the lower end of thecontact carrying member 37 and a spring seat 5? in the insulating base15 provides contact pressure in the closed position of the breaker andalso biases the contact structure in opening direction.

The movable contact structure is normally maintained in the closedposition by an operating mechanism indicated generally at 61 (Fig. 2)mounted in a U-shaped frame 63. The frame 63 comprises spaced sidemembers 65 (Figs. 1 and 2) and a connecting cross member 67. The frame'63 is supported on a platform 69 which forms the cross member of a mainbracket comprising a pair of shown) joined at their outer ends by thecross member or platform 69. The platform extends across the width ofthe breaker and the side members 71 are rigidly secured to the metalpanel 17 on the outside of the two outer pole units.

The operating mechanism includes a lever '73 pivotally mounted on apivot pin 75 supported in the side member 65 of the frame 63. The lever73 comprises a pair of spaced levers joined by a cross member 77 andbetween them support a rod 79 which extends across all three poles ofthe breaker. The rod 79 is operatively connected by means of aninsulating connecting member 3.1 to the pivot pin 41 in the free end ofthe switch member 43 on which the movable contact member 37 is mounted.There is a connecting member 81 for each pole of the breaker connectingthe rod 79 to the moving contact structure for each pole unit so thatupon operation of the rod 79 the movable contact structure for all threepoles move in unison.

An operating linkage comprising toggle links 83, 85 and 87 (Fig. 2) isprovided to hold the lever 73 and consequently the movable contacts inthe closed position and to operate the movable contacts to open andclosed positions. The toggle link 83 is pivotally connected to the lever73 by a pivot pin 89 and the toggle link 85 is connected by a knee pivotpin 91 to the toggle link 83 and by a knee pivot pin 93 to the togglelink 37. The toggle link 87 is pivotally mounted on a tired pivot 97 inthe frame 63 and has a cam member 95 thereon.

The linkage 83, 85, 87 comprises two toggles, one of which 83, 85,functions as a tripping toggle a d the other 85, .87 as a closingtoggle. The tripping toggle 83, S5 is normally slightly underset above aline drawn through the pivot pins 89, 93 and the closing toggle 85, 87is normally underset below a line drawn through the pivots collapsing bymeans of a main latch member 99 pivoted on the pivot pin 75 andconnected by a link 101 to the knee pin 91 of the tripping toggle, thelink 101 being connected to the latch member 99 by a pivot pin 103.

The main latch 99 is held in latching position by an intermediate latchlever 105 pivoted on a pin 107 supported in the frame 63. The latchlever 105 carries a latch roller 111 which normally engages the mainlatch -99 to releasably restrain the latter in holding position.

The latch lever 105 at its lower end carries a latch member 113 engaginga light-load latch 115 mounted on a channel-shaped member 117 pivotallymounted on a pin 119 supported in the frame 63. The latch lever 105 andthe member 117 are biased to their latching positions by a spring 121tensioned between the parts as shown in Fig. 2. Rigidly mounted on theright hand end of the channelshaped member 117 is a trip bar 123 whichextends across all of the poles of the breaker and has secured theretoan insulating bracket 125 for each pole of the breaker. Each of thebrackets 125 has a headed screw 127 adjustably mounted therein forcooperating with the trip device 13 for the corresponding pole unit in amanner to be later described.

As long as the main latch 99 is held in latching position by thelatching mechanism just described, the tripping toggle 83, 85 will,through the link 101, be held in the position shown in which the breakercontacts are held in the closed position. The closing toggle 85, 87 isnormally biased in a direction to cause its collapse by a spring 129 butis normally prevented from collapsing by a shouldered support member 131pivoted on the pin 107 and biased by a spring 133 into supportingengagement with the knee pin 93 of the closing toggle.

Rigidly secured to the front plate or cross member 67 of the frame 63 isa bearing member 135 in which is rotatably mounted a handle shaft 137 tothe outer end of which is secured an operating handle (not shown).Secured to the inner end of the shaft 137 is a cam member 149 which hasthe dual function of engaging the free end of the channel-shaped member117 to manually trip the breaker upon movement of the handle in onedirection and of engaging the cam 95 on the closing toggle 85, 87 tomanually close the breaker upon movement of the handle in the oppositedirection. The cam member 149 and the handle are biased in bothdirections to a central position in a well known manner by means of aspring 145.

Assuming the circuit breaker to be in the closed and latched position(Fig. 1) with the support member'131 supporting the closing toggle 85,87 in its extended thrust transmitting position, the breaker is trippedopen by manually rotating the handle shaft 137 in the proper direction.During this movement the cam member 149 engages and actuates thechannel-shaped member 117 to disengage the latch member 115 from thelatch 113 whereupon the force exerted by the springs 57 biasing theswitch arms 43 in opening direction and transmitted through theconnecting members 81, the rod 79 and the lever 73, causes the trippingtoggle 83, 85 to collapse upwardly and effects opening movement of themovable contacts for all of the poles of the breaker.

The closing toggle 85, 87 does not immediately collapse followingrelease of the latch mechanism since it is held by the support 131.During the collapsing movement of the tripping toggle 83, 85 the togglelink 85 rotates counterclockwise about the pivot pin 93 causing an ear153 formed on the link 85 to engage and move the support member 131 todisengage the shoulder thereon from beneath the pin 93 whereupon thetoggle 85, 87 collapses downwardly under the bias of the spring 129 andthe weight of the moving armature of a closing solenoid, which will bedescribed later. Collapse of the closing toggle 85, 87 causes resettingof the tripping toggle 83, 85 to thrust transmitting positions andresetting of the latching mechanism to latching positions. The mechanismis now in condition for a closing operation.

The contacts are closed either manually by operation of the shaft 137 bythe handle or by operation of a closing solenoid indicated generally at159. In order to close the contacts manually, the shaft 137 is rotatedin the direction opposite to the direction it is rotated to manuallytrip the breaker. This operation of the shaft 137 engages the cam member149 with the cam on the closing toggle link 87 and straightens theclosing toggle 85, 87. Since, at this time, the knee of the trippingtoggle 83, 85 is restrained by the latching mechanism, the thrust ofstraightening the closing toggle 85, 87 is transmitted through thetripping toggle to rotate the lever 73 in a clockwise direction to closethe contacts. As the knee pin 93 of the closing toggle 85, 87 arrives atthe fully closed position the support 131 is moved by the springs 133into supporting engagement with the knee pin 93 to maintain the contactsclosed. I

The circuit breaker is closed automatically by energization of theclosing solenoid 159 (Figs. 1 and 2) which is effected either manuallyor automatically by closing a suitable switch (not shown). The solenoid159 comprises a fixed magnet yoke 161 and a fixed core member 169supported on brackets 163 secured to the underside of the platform 69. Amovable armature 171 is attached to the lower end of an operating rod173 which extends upwardly and has its upper end pivotally connected tothe knee pivot pin 93 of the closing toggle 85, 87. An energizing coil175 Wound on an insulating spool is supported on the fixed magnet yoke161.

In the closed position of the breaker the armature 171 is held in itsraised position as shown in Fig. 2. When the breaker is tripped open theclosing toggle 85, 87 collapses permitting the armature 171 to assumeits lower or unattracted position. Thereafter, upon energization of thecoil 175, the armature 171 is attracted upwardly straightening thetoggle 85, 87 and closing the breaker contacts.

The circuit breaker is automatically tripped open by operation of thetrip device 13 for any pole of the breaker. The trip device includes atripping electromagnet indicated generally at 177 (Figs. 1, 2 and 3) anda time delay device indicated generally at 179. The trippingelectromagnet 177 comprises a C-shaped magnet yoke 181 rigidly securedto the base 15 by means of bolts 183 and 185 (Fig. 2), a fixed coremember 187 (Fig. 3), an energizing winding 139, a movable armature 191and an instantaneous tripping armature 192. The bolt 183 (Fig. 2) whichsecures the upper end of the magnet yoke 181 to the base 15 also securesthe lower end of the flexible conductor 51 to the upper turn of thewinding 189. The lower turn of the winding 189 has a conducting lug 193electrically and mechanically secured thereto and this lug is secured toa conducting terminal 195 and to the base 15 by means of a bolt 197. Theenergizing winding 189 is thus electrically connected in series relationin the circuit through the breaker which circuit extends from theterminal 27, the main and arcing contacts 23, 33 and 25, 35, the contactmember 37, flexible conductor 51, energizing coil 189 of the trip magnetto the terminal 195. Upon energization of the tripping magnet thearmature 191 is attracted upwardly and actuates a trip 'rod 199 whichengages the headed screw to operate the trip bar 123 and trip thebreaker.

The movable armature 191 comprises an upper cupshaped member 201 and alower tubular member 203 both of magnetic material and rigidly securedtogether. The member 201 has a central opening therein and is adapted toslide over a sleeve 205 surrounding the trip rod 199. The sleeve 205 islimited in its upward movement relative to the trip rod 199 by means ofa spring clip 207 seated in an annular groove in the trip rod. A spring209 coiled about the trip rod 199 is compressed between the lower end ofthe sleeve 205 and the bottom of a counterbore 211 in the lower element203 of the movable armature.

The fixed core member 187 (Fig. 3) is clamped to the upper leg of themagnet yoke 181 by means of a thimble 139 the bore of which acts as aguide for the trip rod 199.

The trip rod 199 is moved upwardly to trip the breaker under the controlof the time delay device 179 which comprises a flexible diaphragm 213(Fig. 3) attached to the lower end of the trip rod 199 and valve meansfor admitting air to the space below the diaphragm at various rates toprovide different amounts formed in an upper housing member 217 and alower housing member 219, both of the housing members being formed ofmolded insulating material. The outer edge of the diaphragm 213 isclamped between the housing members 217 and 219, together with a sealinggasket 221 to thereby form an air-tight seal. The housing members aresecured together and rigidly secured to the lower leg of the magnet yoke181 by means of bolts 223 (Figs. 3 and 4). The central portion of thediaphragm 213 is clamped between upper and lower clamp members 225 and227 respectively, the upper clamp member 225 having an annularprojection 229 extending downwardly through an opening in the lowerclamp member 227 and formed over against the lower face of the latter toform an air-tight seal.

Secured to the lower end of the trip rod 199 is a sleeve 231 having aflange 233 thereon rigidly secured to the upper clamping member 225. Thelower portion 203 of the movable armature extends downwardly through anopening in the upper wall of the chamber 215 above the diaphragm 213 andis seated on the upper face of the clamping member 225 being biasedthereagainst by the spring 209.

Since the spaces above and below the diaphragm 213 are completely sealedoff from each other and the space above the diaphragm is at atmosphericpressure, any force tending to raise the trip rod 199 will be restrainedby the partial vacuum below the diaphragm. In order to control the rateof tripping movement of the trip rod 199 valve devices indicatedgenerally at 235 (Fig. 3) and 237 (Fig. 5) are provided to admit air tothe space below the diaphragm 213 at different rates to provide a longtime delay and a short time delay respectively in the operation of thetrip rod.

The central bottom portion of the housing member 219 is molded to form avalve seat 241 in the shape of an inverted truncated cone. Surroundingthe valve seat 241 is a tubular metallic member 243 molded into thehousing member 219 and threaded internally to receive a valve 245 havinga conical opening therein for cooperating with the valve seat 241. Thevalve 245 is provided with a flange 247 for supporting an adjusting knob249 of insulating material which is biased thereagainst by a spring 251coiled about the tubular member 243 and compressed between the bottom ofthe housing member 219 and the upper surface of the knob 249, a flange253 on the knob 249 cooperates with a flange 255 on the housing member219 to support a filter 257 for filtering the air admitted to thechamber 215 below the diaphragm. A passage 259 is provided along thethreaded surface of the valve 245 and a passage 261 extends axiallythrough the valve seat 241 to admit air to the chamber 215 below the diaphragm. Rotation of the knob 249 rotates the valve 245 which moves thevalve axially of the valve seat 241 to vary the rate of admission of airto the chamber below the diaphragm thereby varying the amount of timedelay provided in the operation of the trip device.

The short time delay device 237 (Fig. 5) controls a passage foradmitting air from the chamber 215 above the diaphragm 213 to the spacebelow the diaphragm at a rate to provide a short time delay in the orderof alternating current cycles in the tripping of the circuit breaker.The valve device 237 comprises a tubular valves element 273 (Fig. 5)disposed in an opening 275 in the housing member 217 and having anenlarged head portion 277 seated in an opening 279 in the housing member219. The valve element 273 is provided with a valve seat and a valve281, slidable in the tubular valve element 273 normally cooperates withthe valve seat to close a communication with opposite sides of thediaphragm. The valve element 273 is provided with an axial passage 283in which is disposed a tapered projection 285 on the valve 281 and whichis normally closed by the valve 281. The head 277 of the valve element273 is provided with horizontal passages 287 disposed at right angles toeach other. A passage 289 in the housing member 217 communicates thechamber 215 above the diaphragm 213 with the opening 275 above the valveseat and a passage 291 in the housing member 219 communicates thechamber 215 below the diaphragm 213 with passages 287 in the portion 277of the valve element 281. The valve element 273 is held in place by aplug 292 threaded into the opening 279 in the housing member 219.

It will be seen that upward or opening movement of the valve 281 willopen the passage 283 and establish a communication from the upper sideto the lower side of the diaphragm 213 through the passage 289, 283, 287and 291. The valve 281 is actuated to open position by means of anarmature 293 (Figs. 4 and 5) which is biased to unattracted position bya spring 294 and which is attracted upwardly by the tripping magnet 177when the magnet is energized by overload circuits in an intermediaterange of overloads of, for instance, 200% to 1000% of normal ratedcurrent. An opening 296 (Fig. 5) in the lower leg of the magnet yoke 181provides an air gap for the magnetic circuit through the armature 293.The armature 293 is provided with laterally extending projections 295(Fig. 4) which are seated in recesses 297 in the upper portion of thehousing member 217 to pivotally support the armature. A bracket 299(Figs. 4 and 5) secured to the armature 293 has a semi-circular opening303 (Fig. 4) therein which engages in a notch 305 in the upper end ofthe valve so that upon actuation of the armature 293 the bracket 299engages a substantially semicircular head 307 on the valve 281 and movesthe valve to open position. This opens the previously describedcommunication and permits air to pass from the chamber 215 above thediaphragm 213 to the space below the diaphragm to control the trippingmovement of the trip rod 199 (Fig. 3). The rate of flow of air to thespace below the diaphragm, and consequently the rate of trippingmovement of the trip rod, is controlled by the amount of opening of thevalve 281.

The extent of opening movement of the valve 281 is adjustably controlledby means of an adjustable S- shaped stop member 309 (Fig. 5). The upperportion 311 of the S-shaped member 3139 comprises an adjustable stopdisposed in the path of tripping movement of the free end of thearmature 293 to limit the upward movement of the armature 293 and theextent of opening of the valve 281. The center cross bar 313 theS-shaped member 309 has a threaded opening therein which is engaged by areduced threaded portion 315 of an adjusting screw 317, so that uponrotation of the screw the S-shaped member 309 will be moved up or down,depending on the direction of rotation of the screw, to provide forgreater or lesser movement of the armature 293 and, hence, greater orlesser opening movement of the valve 231.

The screw 317 extends through an opening in a cross member 321 ofinsulating material and has an insulating knob 319 secured to its lowerend. The cross member 321 is secured to the underside of the housingmember 217 by means of screws 323 only one of which is shown. Anenlarged threaded portion 335 of the ad justing screw 317 passes througha clearance opening 'in the lower portion of the S-shaped member andthreadedly engages an indicating member 337. A pointer 339 at the outerend of the member 337 extends through a vertical slot 340 in an indexplate 341 supported at its lower end on the cross member 321 and havingits upper end secured to a cross member 343 integral with the housingmember 217.

The pickup point, that is, the magnitude of overload current required toactuate the armature 293 may be varied by varying the tension of thespring 294. The upper end of the spring 294 is attached to the armature293 and the lower end of the spring is attached to a movable member 391(Fig. 4) which threadedly engages an adjusting screw 395. The screw 395is rotatably mounted in the cross member 321 and has an adjusting knob396 (Fig. 6) on the lower end thereof below the cross member 321.Rotation of the screw 395 will move the member 391 up or down to varythe tension of the spring 294, thus varying the pickup point of thearmature 293. The movable member 391 is provided with a pointer 393extending through a vertical slot in the index plate to prevent rotationof the movable member and to indicate the setting of the device.

Similarly the pickup point for the movable armature 19 (Fig. 3) of thetripping electromagnet 177 may be adjusted. The armature 191 is biasedto its unattracted position by means of springs 405 (Figs. 3 and 4)having their upper ends attached to a U-shaped yoke 407 which has itstwo legs pivotally supported in spaced, grooved studs 409 supported onthe housing member 217 substantially as shown in Figs. 3 and 4. Theright hand end of the yoke 407 engages an annular groove 413 (Fig. 3) inthe lower member 203 of the armature 191. The lower ends of the springs405 are attached to a movable member 415 which is threadedly engaged byan adjusting screw 417. The lower end of the adjusting screw 417 isrotatably mounted in the cross member 321 and has an insulating knob 419secured to its lower end below the cross member 321. A pointer 421 onthe movable member 415 extends through a slot in the scale plate 341 toprevent the movable member from turning and to indicate the setting. Itwill be understood that the scale plate 341 bears indicia adjacent theseveral pointers indicating the settings of the several adjustingdevices.

The trip device operates with time delays of different durations in tworanges of overcurrents below a predetermined magnitude. These ranges ofovercurrents may be arbitrarily defined as, for example, a low range upto 500% or 600% of normal rated current, and a high range between 500%or 600% and 1000% of normal rated current. The circuit breaker will alsotrip open instantaneously in response to excessive currents above 1000%of normal rated current, or short circuit currents, but only during aclosing operation when the breaker closes in against such a faultcurrent, since means, to be hereinafter described, is provided to renderthe instantaneous tripping means effective only during a closingoperation of the breaker.

Upon the occurrence of an overcurrent in the low range the trippingelectromagnet becomes energized and attracts the armature 191 (Fig. 3)upwardly. The armature acts through the spring 209 and the sleeve 205 toproduce an upward thrust on the trip rod 199, the movement of the triprod being retarded by the partial vacuum below the diaphragm 213. Thetrip rod 199 moves up slowly in tripping direction as air is drawn intothe space below the diaphragm through the long time delay valve 235until the upper end of the trip rod engages the headed screw 127(Fig. 1) and actuates the latch mechanism to effect tripping of thebreaker in the manner previously described. The time delay provided bythe long time delay valve device 235 is in the order of seconds and maybe varied by adjusting the valve 241, 245 as set forth previously. Aspring biased bypass valve 425 (Fig. 3) controls a passage through thediaphragm 213 to provide for quick restoration of the armature 191, thetrip rod 199 and the diaphragm 213 to their normal positions following atripping operation.

An overcurrent in the high range of overcurrents, but below 1000% ofnormal rated current, energizes the tripping electromagnet 17'7sufiiciently to attract the valve actuating armature 293 (Fig. upwardlyagainst the adjustable stop 311 opening the short time delay valve 281.This admits air to the space below the diaphragm 213 at an increasedrate and provides a relatively short time delay in the order cycles inthe operation of the trip device.

As previously set forth the armature 192 is provided to effectinstantaneously tripping of the breaker in response to excessive faultcurrents or short circuit currents. It was also pointed out previouslythat the circuit breakers in certain locations in a selective trippingsystem are capable of carrying excessive currents for a certain lengthof time without damage to the breaker, the length of time the circuitbreaker will carry such excessive overload currents being determined bythe setting of the short time delay device. The critical time in theoperation of the breaker when damage is most likely to occur is inclosing the breaker in against an excessive fault current. or shortcircuit current. For this reason the instantaneous armature willfunction to effect instantaneous tripping of the breaker only during aclosing operation of the breaker and then only when the breaker contactsclose against an excessive fault current.

The armature 192 is similar to the armature 293 and is provided withprojections 379 (Figs. 3 and 4) for pivotally supporting the armature192 in the recess 297 in the upper face of the housing member 217. Thefree end of the armature 192 is biased by means of a spring 381 to itsunattracted position. The magnet yoke 181 is provided with an opening(not shown) similar to the opening 296 (Fig. 5) which provides an airgap for the The pickup point, that is, the magnitude of overload currentrequired to actuate the armature 192 may be varied by varying thetension of the spring 381. The upper end of the spring 381 is attachedto the armature 192 and the lower end is attached to a movable member383 (Fig. 4) which is threadedly engaged by an adjusting screw 385. Thelower end of the adjusting screw 385 is rotatably mounted in the crossmember 321 and has an adjusting knob 337 secured to its lower end belowthe cross member 321. A pointer 389 on the movable member extendsthrough a slot in the scale plate 341 to prevent the member 383 fromturning and to indicate the setting.

When the electromagnet 177 (Fig. 3) is energized by a fault current of,for instance, ten times normal rated current, as a short circuitcurrent, it attracts the armature 192 upwardly during which movement thefree end of the armature engages and actuates a switch indicatedgenerally at 344. A plunger 345 is slidably mounted in the cross member343 of the housing member 217 and, at its upper end, the plunger 345carries a bridging contact member 347 for cooperating with spacedstationary contacts 349 in the switch 344 which is enclosed in aninsulating housing 351.

Referring to Fig. 7, which comprises a schematic illustration of thecircuit breaker, there is a switch 344 associated with the trip device13 for each pole of the breaker. The switches 344 are connected inparallel relation in a circuit which extends from one side of a sourceof electrical energy 353, a wire 355, any one of the switches 344, awire 357, an auxiliary switch or contacts 359 on the circuit breakerwhich are open when the breaker is closed and closed when the breaker isopen, a wire 361, the coil of a shunt trip device 363 (see also Fig. 1)to the other side of the source 353. A switch 365 is provided formanually energizing the shunt trip device 363 to trip the breaker.

The armature 192 (Figs. 3, 4, 7 and 8) will function to close the switch344 whenever an overload current of ten times normal rated current or ashort circuit occurs. However, when the breaker is standing closed, theauxiliary contacts 359 (Fig. 7) are open, so that closure of one or moreof the switches 344 will not energize the shunt trip 363. If the breakeris closed in against a fault of sufficient magnitude, the switch 344will close at the instant the arcing contacts 25-35 (Figs. 1 and 2)touch and, since at this time, the auxiliary contacts 359 (Fig. 7) havenot opened, the shunt trip coil will be energized and its armature 367(Fig. 1) will actuate a bell crank 369 which, in turn, actuates the tripbar 123 to trip the breaker open instantaneously.

If there is no fault of sufiicient magnitude on this line when thebreaker closes the mechanism will go to the fully closed and latchedposition. Between the time the breaker contacts touch and the mechanismis latched, the auxiliary contacts 359 (Fig. 7) opens so that a shortcircuit current occurring thereafter will cause tripping of the breakerwith a short time delay and with a long time delay in the case of anoverload current in the previously described manner.

The invention provides a circuit breaker having trip means and timedelay means for providing long and short time delay in the operation ofthe trip device and also means for instantaneously tripping the breaker,there being also provided means for rendering the instantaneous tripmeans effective only When the breaker is closed with a fault on theline.

Having described the invention in accordance with the provisions of thePatent Statutes, it is to be understood that various changes andmodifications may be made in the structural details and combination ofelements disclosed without departing from some of the essential featuresof the invention.

I claim as my invention:

1. In a circuit breaker having relatively movable contacts, operatingmeans for opening and closing said contacts, a movable member movable toeffect automatic opening of said contacts, a first trippingelectromagnet comprising an energizing winding and an armature operativeupon energization of said winding by overload currents below apredetennined value to move said movable member, time delay means foreffecting a time delay in the operation of said movable member by saidarmature, a second tripping electromagnet operative when energized formovingsaid movable member, a

second armature operative instantaneously upon energization of theenergizing winding for said first tripping electromagnet by overloadcurrents above said predetermined value, contact means operative by saidsecond armature of said first tripping electromagnet for effectingenergization of said second tripping electromagnet to thereby causeinstantaneous movement of said movable member, and auxiliary contactmeans positioned according to the positions of said breaker foreffecting energization of said second tripping electromagnet only duringclosing operations of said breaker.

2. ln a circuit breaker having relatively movable contacts, operatingmeans for said contacts, a movable member movable to effect automaticopening of said contacts, a first tripping electromagnet operative whenenergized by overload currents below a predetermined value to move saidmovable member, time delay means for effecting a time delay in themovement of said movable member by said first tripping electromagnet, asecond tripping electromagnet operative when energized toinstantaneously move said movable member, contact means instantaneouslyclosed by said first tripping electromagnet when said first trippingmagnet is energized by overload currents above said predetermined valueto effect energization of said second tripping electro magnet andinstantaneous movement of said movable member, and an auxiliary switchcontrolled by said circuit breaker for effecting energization of saidsecond tripping electromagnet only during closing operations of saidbreaker.

3. In a circuit breaker having relatively movable contacts, operatingmeans for said contacts, a movable member movable to effect automaticopening of said contacts, a first tripping electromagnet operative whenenergized by overload currents below a predetermined value to move saidmovable member, time delay means for effecting a relatively long timedelay in the movement of said movable member by said first trippingelectromagnet, means for controlling said time delay means to effect arelatively short time delay in the movement of said movable member bysaid first tripping electromagnet, a second tripping electromagnetoperative when energized to instantaneously move said movable member,contact means instantaneously closed by said first trippingelectromagnet when said first tripping magnet is energized by overloadcurrents above said predetermined value to effect energization of saidsecond tripping electromagnet and instantaneous movement of said movablemember, and an auxiliary switch controlled by said circuit breaker foreffecting energization of said second tripping electromagnet only duringclosing operations of said breaker.

4. In a multi-pole circuit breaker having relatively movable contactmeans in each pole of said breaker, operating means for said movablecontact means, a movable member common to all of the poles of saidbreaker movable to effect automatic opening of said contact means, anovercurrent trip device in each pole of said breaker operative whenenergized by overcurrents below a predetermined value to move saidmovable member, a time delay device for each of said overcurrent tripdevices for effecting a time delay in the movement of said movablemember by said overcurrent trip devices, electroresponsive meansoperative when energized to instantaneously move said movable member,contact means on each of said overcurrent trip devices operative uponenergization of any one of said overcurrent trip devices to effectenergization of said electroresponsive means, and auxiliary contactmeans on said operating means for effecting energization of saidelectroresponsive means only during a closing operation of saidoperating means.

5. In a multi-pole circuit breaker having relatively movable contactmeans in each pole of said breaker, operating means for said movablecontact means, a movable member common to all of the poles of saidbreaker movable to effect automatic opening of said contact means, anovercurrent trip device in each pole of said breaker operative whenenergized by overcurrents below a predetermined value to move saidmovable member, a time delay device for each of said overcurrent tripdevices for effecting a relatively long time delay in the movement ofsaid movable member by said overcurrent trip devices, means on each ofsaid overcurrent trip devices for controlling the associated time delaydevice to eifect a relatively short time delay in the movement of saidmovable member by said overcurrent trip device, electroresponsive meansoperative when energized to instantaneously move said movable member,contact means on each of said overcurrent trip devices operative uponenergization of any one of said overcurrent trip devices to effectenergization of said electroresponsive means, and auxiliary contactmeans on said operating means for effecting energization of saidelectroresponsive means only during a closing operation of saidoperating means.

6. In a circuit breaker having relatively movable contacts, operatingmeans for opening and closing said contacts, a movable member movable toeffect auto matic opening of said contacts, a first trippingelectromagnet comprising an energizing winding, an armature operativeupon energization of said winding by overload currents below apredetermined value to move said movable member, a time delay device foreffecting a time delay in the operation of said movable member by saidarmature, a second tripping electromagnet operative when energized formoving said movable member, a second armature operative instantaneouslyupon energization of said energizing winding for said first trippingelectromagnet by overload currents above said predetermined value,switch means operative by said second armature of said first trippingelectromagnet for effecting energization of said second trippingelectromagnet to thereby cause instantaneous movement of said movablemember, means adjustable to selectively determine the minimum overloadcurrent required to actuate said second armature, and auxiliary contactmeans operated by said circuit breaker for effecting energization ofsaid second tripping electromagnet only during a closing operation ofsaid breaker.

In a circuit breaker having relatively movable contacts, operating meansfor said contacts, a movable member movable to effect automatic openingof said contacts, a first electromagnetic means for moving said movablemember, time delay means comprising a fluid dashpot for effecting a timedelay in the operation of said movable member, a first valve foradmitting fluid to said dashpot at a predetermined rate for effecting along time delay in the operation of said movable member, a second valvefor admitting fluid to said dashpot at a greater rate than said firstvalve for effecting a short time delay in the operation of said movablemember, a valve operating armature operative when said electromagnet isenergized in response to overload currents below a predetermined valuefor actuating said second valve, a second electromagnetic meansoperative when energized to instantaneously move said movable member,switch means for effecting energization of said second electromagneticmeans, a switch actuating armature operative when said firstelectromagnet is energized in response to overload currents above saidpredetermined value for actuating said switch means to effectenergization of said second electromagnetic means, and auxiliary switchmeans operative according to the position of said breaker to effectenergization of said second electromagnetic means only during a closingoperation of said breaker.

Lammers, Jr. Mar. 28, 1922 Thumim Feb. 24, 1942

